A four-gene expression ratio test prospectively distinguished mesothelioma patients who had a statistically significant longer overall survival from those who had shorter survival, according to researchers from the Brigham and Women's Hospital.

The team’s previous retrospective studies found that measuring expression ratios of four genes could distinguish between those who have a good prognosis after surgery and those who have a poor prognosis. They thus decided to validate their findings in a prospective study, which is reported in the Journal of the National Cancer Institute in a paper titled “Four-Gene Expression Ratio Test for Survival in Patients Undergoing Surgery for Mesothelioma.”

In the current investigation, they tested the four-gene expression ratio test in 120 patients with mesothelioma who were treated at the hospital and participated in a prospective clinical trial. To evaluate the robustness and reproducibility of the test, the researchers evaluated the test on multiple tumor samples from each patient and used two different microarray platforms and two different biopsy techniques.

The test was able to predict overall survival after adjusting for other clinical factors. The results were consistent for individual patients regardless of the techniques used. When the researchers combined the gene ratio test results with known prognostic factors, they were able to separate patients into high-risk and low-risk groups. The median survival for patients in the high-risk group was 6.9 months compared with 31.9 months in the low-risk group.